Does Neuronal Recycling Result in Destructive Competition? The Influence of Learning to Read on the Recognition of Faces.

Written language, a human cultural invention, is far too recent a development for dedicated neural infrastructure to have evolved in its service. Newly acquired cultural skills, such as reading, thus recycle evolutionarily older circuits that originally evolved for different, but similar, functions (e.g., visual object recognition). The destructive-competition hypothesis predicts that this neuronal recycling has detrimental behavioral effects on the cognitive functions for which a cortical network originally evolved. In a study with 97 literate, low-literate, and illiterate participants from the same socioeconomic background, we found that even after adjusting for cognitive ability and test-taking familiarity, learning to read was associated with an increase, rather than a decrease, in object-recognition abilities. These results are incompatible with the claim that neuronal recycling results in destructive competition and are consistent with the possibility that learning to read instead fine-tunes general object-recognition mechanisms, a hypothesis that needs further neuroscientific investigation.